An estimated worldwide total of 62 trillion spam emails were sent in 2008

Globally, annual spam energy use totals 33 billion kilowatt-hours (KWh), or 33 terawatt hours (TWh). That’s equivalent to the electricity used in 2.4 million homes in the United States, with the same GHG emissions as 3.1 million passenger cars using two billion United States gallons of gasoline

Spam filtering saves 135 TWh of electricity per year. That’s like taking 13 million cars off the road

If every inbox were protected by a state-of-the- art spam filter, organizations and individuals could reduce today’s spam energy by approximately 75 percent or 25 TWh per year. That’s equivalent to taking 2.3 million cars off the road

The average GHG emission associated with a single spam message is 0.3 grams of CO2. That’s like driving three feet (one meter) in equivalent emissions, but when multiplied by the annual volume of spam, it’s like driving around the Earth 1.6 million times

A year’s email at a typical medium-size business uses 50,000 KWh; more than one fifth of that annual use can be associated with spam

Filtering spam is beneficial, but fighting spam at the source is even better. When McColo, a major source of online spam, was taken offline in late 2008, the energy saved in the ensuing lull — before spammers rebuilt their sending capacity — equated to taking 2.2 million cars off the road

Much of the energy consumption associated with spam (52 percent) comes from end-users deleting spam and searching for legitimate email (false positives). Spam filtering accounts for just 16 percent of spam-related energy use

On the positive side, think of the boom in penis enlarger sales, which is what we clearly need in these harsh economic times.